Objective: In order to be reimbursed for the care they provide, hospitals in the United States are required to use a standard system to code all discharge diagnoses: the International Classification of Disease, 9th Revision, Clinical Modification (ICD-9). Although ICD-9 codes specific for child maltreatment exist, they do not identify all maltreatment-related hospital and emergency department discharges. To increase the usefulness of medical data for public health surveillance of child maltreatment, this project sought to identify ICD-9 codes that are suggestive of child maltreatment. Methods: After review of the literature and discussions with experts, injuries and conditions that should raise suspicion of child maltreatment (physical or sexual abuse or neglect) were identified and a list of corresponding ICD codes was compiled. Using a statewide electronic database of hospital discharges and emergency department (ED) visits for the year 2000, visits by children assigned these ICD codes were identified, a sample of visits was selected, and medical records were reviewed to assess the circumstances of the injury or illness that led to the visit. Based on information in the medical record, the injury or illness was classified as maltreatment-related, or not. Results: There were 3,684 visits selected for review. Of these, 2,826 records were reviewed and classified; 1,200 (43%) records met the criteria for being maltreatment-related, 1,419 (50%) contained adequate information indicating the injury/condition was not likely maltreatment-related, and 207 (7%) records did not contain enough information to classify. Sixty-eight ICD codes had greater than 66% of visits classified as maltreatment-related, the "a priori" criteria for a code to be considered suggestive of maltreatment. Codes suggestive of maltreatment include specific fractures, burns, and injuries of undetermined intent, among others. Conclusion: Several ICD codes were found that, when used with age restrictions and other specific exclusion criteria, are suggestive of maltreatment. This information may increase the usefulness of hospital discharge data for public health surveillance of child maltreatment. Practice implications: Use of these suggestive codes facilitates identifying conditions and injuries that are likely maltreatment-related in hospital discharge and ED visit data. When used in conjunction with ICD maltreatment-specific codes, these suggestive codes may enhance the use of medical data for monitoring child maltreatment trends. (Contains 6 tables.)